Valve for internal combustion engines



Oct. 29, 1935.

G. W. DOUGLAS El AL VALVE FOR INTERNAL COMBUSTION'ENGINES Filed Dec.

INVENTORS BY Jaim Jase/z eufey ORNEYS Patented Oct. 29, 1935 UNITEDASTATES PATENT OFFICE VALVE FOR INTERNAL COMBUSTION ENGINES ApplicationDecember 31, 1934, Serial No. 759,922

8 Claims.

This invention relates in general to valve construction and moreparticularly to improvements in poppet valves for use in internalcombustion engines.

It is essential in the operation of an internal combustion engine, thatthe valves function and seat properly. Such valves, as the poppet type,arranged in the cylinder head are subjected to extreme conditionsbrought about in the combustion chamber tending toward deterioration ofthe valve and malfunctioning thereof. These deteriorations take the formoi carbon deposits, warping, pits, and unevenness of wear of the valveby its contact with its seat. The results are leaky valves or stickingvalves. As long as the valve is pitted or has unevenly distributedcarbon deposits, leaking of the valves and loss of compression willresult. As long as the valve stem is burdened with unevenly distributedcarbon deposits sticking valves will result.

Heretofore it has been the common accepted practice to provide a poppetvalve with a unitary stem against which a cam actuated poppet bears toopen the valve. A spring is provided to return the valve to its seatsubject to the operation of the tappet. The movement of the valve ,ispurely reciprocatory. Now, particularly in connection with the exhaustvalve, one side of the valve seat as well as one side of the valve andstem, are being constantly subjected to more extreme heat and a greatertendency to receive carbon deposits than the other sides is present.

It is therefore an object of this invention to provide a valve and animproved means of operating the valve so that in addition to areciprocatory movement the valve is also slightly rotated during eachcycle of operation so that the wear and the carbon deposits and extremeheat will, by reason of the rotation of the valves, be evenlydistributed on the valve and its stem. In this manner the valve headwill not burn on one side as different parts of the valve are constantlybeing seated on diiferent parts of the valve seat. This will also tendto eliminate carbon deposits on the valve seat as the movement of thevalve will tend to pulverize the carbon.

It is also an object of the invention to provide an arrangement of thisnature for the purpose of preventing broken valve springs, by providingan articulated valve stem so that the part directly connected to thevalve head will be rotatable relatively to that part of the valve stemwhich is spring pressed and cam actuated. In this manner the spring willbe relieved of the usual sudden shock when the valve drops into itsseat.

(Cl. 12S-188) I In the usual design of poppet valve construction i ininternal combustion engines it is necessary to remove the spring inorder to grind or remove the valves. lI'his entails a laboriousoperation and a checking of the spring when it is replaced t5 todetermine its proper functioning when the valve .and its spring areagain assembled for operation.

In order to avoid these difficulties, it is a further object of ourinvention to provide a valve and l0- stem, and means of mounting of thesame whereby it will not be necessary to remove the spring when removingthe valve and further Where it is merely necessary to apply the propertool to the valve head and grind the same against its seat lli Withoutremoving the valve or spring or disturbing the relationshiptherebetween.

In order to make this possible it is proposed to provide an articulatedvalve stem, one part of which will receive the spring and be operated by20 the cam actuated tappet while the other part of the valve stemcarries the valve head, the valve head and its adjacent stem portionbeing recip- -rocable in unison with but rotatable independently of thetappet actuated stem portion. Further- 25,

more, for valve removal and valve grinding purposes, the abuttingportions o1 the articulated stem may be held in place by a removablecoupling so that the upper stem and the head may be removed withoutdisturbing the valve spring. 3 0:

The objects and nature of our invention will become more apparent on afurther reading of the following specification and appended claims,

certain embodiments of the invention being shown in the accompanyingdrawing, in which: 35"

Figure 1 is a fragmentary view in vertical section taken through acylinder head showing the piston and poppet valve in the combustionchamber;

Figure 2 is a view in elevation partly in section 40 of the poppet valveand its articulated stem prior to the compressing operation to join thetwo parts together;

Figure 3 is a viewV similar to Figure 2 of the valve in assembledposition;

Figure 4 is a top plan view of the valve head;

Figure 5 is a fragmentary sectional view similar to Fig. 1 showing amodified form of stem in which the articulated portions are held by aremovable coupling. 50

Referring more particularly to the drawing the cylinder l and its head 2is shown with the usual type of combustion chamber 3. The cylinder isshown as provided with the usual type of piston 4 having a connectingrod 5 connected to the piston 55 fof at I2 is referred to as an exhaustvalve by rea- Y son of the fact that it is the exhaust valve that issubjected to the relatively more strenuous heat conditions. It must beremembered, however, that the improvement constituting our invention isequally applicable to intake valves and therefore our invention consistsin improvements as applied to intake as well as exhaust valves.

Referring to Figure 2 the valve head I2 is provided with the usualrecesses I 3 to receive a suitable tool for grinding operations againstthe valve seat. The valve head is shown provided with a y stem portionI4 which is reduced at I5. This reduced stem may extend downwardly to apoint I6. At one or more points in its reduced diameter it may beprovided with peripheral grooves, three of which are shown in Figure 2at I1. 'Ihe number of grooves provided is merely a matter of choice. Thevalve stem I4 together with its reduced portion I5 does not constitutethe proper length of the valve stem for operating purposes. It may be ofany desired length so as to cooperate with the lower portion shown at I8to constitute a valve stem of proper operating length. This lowerportion I8 of the valve stem is centrally bored so as to snugly butrotatably receive the reduced portion I5. As shown in Figure 2 the upperportion of the valve stem I8 may be enlarged, as shown at I9. Inassembling the two parts together it is merely necessary to press theenlarged portion I9 radially inwardly, at which time the smooth innersurface of the enlarged portion I9 will be formed into ribs onprojections 20 by being pressed into and fitting in the grooves I1 ofthe reduced portion I5. The grooves I1 however are not spiral but areexactly perpendicular to the length of the valve stem; It is importantand essential that the relationship of the projections 20 and thegrooves I1 be such as to allow free relative rotation between the valvestem portions I4 and I 8. The enlarged portion I9 is then machined downso as to conform with the outer diameter of the remaining portion of thestem portion I8. The bottom I6 of the reduced portion I5 fits in andbears upon the bottom of the bore in the stem portion I8. The stemportion I8 is also provided with an oil groove 2| extending from thebottom of the stem portion I8 upwardly so as to communicate with thebore which receives the reduced portion I5. 'Ihe stem portion I8 is alsoprovided with a peripheral groove 22 to receive a washer 23.

In assembling the valve in the internal combustion engines it is merelynecessary to push the composite articulated valve stem downwardlylthrough the valve stem guide B. A compression coil spring 24 may thenbe placed around the valve stem guide portion 25 so as to rest againstthe shoulder 26. The valve stem may then be compressed and the washer 23removably secured to 'stem I 8 by means of groove 22. The coil spring 24when thus assembled has a tendency to pull the valve head downwardlyagainst its seat 21. The cam actuated tappet for raising the valve offits seat against the action of the compression spring is shown at 28 andmay be of any convenient and conventional design.

Due to the flow of the exhaust gases in the combustion chamber, as shownby the arrows, that portion of the cylinder shown at 30 is beingsubjected to relatively more extreme heat than the remaining sides ofthe cylinder. The valve head has been generally referred to at I2 andthe valve seat has also been generally indicated at 21 but it will beseen that if the valve head remained in this fixed position, other thanits reciprocatory movement, that portion of the vvalve head indicated atI2' would be subjected to relatively greater temperatures and carbondeposits than would the remainder of the valve head by reason of thefact that this portion I2' would be the only portion of the valve headthat would be contacting with that portion of the valve seat indicatedat 21 and further would always bein Ythe position directly opposing theiiow of hot exhaust gases. It follows that the valve stem, if it did notrotate, would also be subjected on its side facing the direction of ilowof the exhaust gases to a relatively greater extreme heat and carbondeposits than would the remainder of the valve stem.

However, by the present arrangement, when the tappet 23 pushes upwardlyon the valve stem, the compression of the spring 24 tends to slightlyrotate the lower portion of the valve stem. While the upper portion ofthe valve stem is free to rotate with relation to the lower portion ofthe valve stem, nevertheless a slight rotation is imparted to the valvehead due to the twisting action of the spring and a small degree .ofdrag in the relative rotational relationship between the two valve stemcomponents. On the downward movement of the valve stem brought about bythe compression spring that portion of the valve head indicated at I2will contact with a different portion of the valve seat than that fromwhich it has been immediately removed. Likewise the expansion of thespring would tend to give'a reverse twist to the lower portion of thevalve stem, but the valve head contacts its seat prior to this so thevalve head remains advanced on its seat. Moreover, in view of the factthat the valve head is rotatable, it will be free to turn as its seatsso as to tend to correct any unevenness on the valve head heatingsurface as well as the surface of the valve seat.

Thus by reason of the fact that the valve stem and valve head are freeto rotate the extreme heat conditions to which they are subjected isevenly distributed throughout all sides thereof. This minimizes andtends to eliminate warping of the valve head and the formation of carbondeposits and pits in the valve head, valve stem or seat. The carbonwhich would otherwise be deposited on the valve seat will be pulverizedby reason of the possible rotary movement of the valve as it returns toits seat under the urging of the compression sp-ring. l As a furtherrefinement tending towards the elimination of sticking valves there maybe provided an oil groove 2! up through which oil may flow so as to comebetween the outer surface of the reduced portion I5 and the innersurface of the lower valve stem I8. Moreover oil in flowing past theseadjacent surfaces may also iiow out between the slight space between thejunction point indicated at SI between the upper and lower valveportions so as to provide a lm lubrication for the composite valve stemwithin its guide.

It will be readily seen that when it is desired to grind valves it ismerely necessary to engage the head portion with a suitable tool androtate the same after the camshaft has been rotated in such a positionthat the valve head rests approximately against its seat, leaving, ofcourse, sufcient clearance to receive the valve grinding component.Inasmuch as the valve head and the upper stem portion is rotatable withrelation to the lower valve stem portion, such a rotation in thegrinding operation may be freely performed without consideration of thecompression spring 24. In other words, the grinding operation, asdistinguished from the conventional practice, does not entail theremoval of the Valve spring.

The same holds true in connection with the form of the invention shownin Figs. 5 and 6, in which the valve stem is shown as comprising anupper portion 40 and a lower portion 42. rIhe upper stern 40 is providedwith a suitable number of grooves 4l and the lower stem 42 with grooves43. The stems are placed so as to abut each other and held in placepreferably by a removable coupling. The coupling may consist of twosemicylindrical members 46 and 44 respectively provided with innerflanges 41 and 45 each to engage the grooves 4| and 43 of the stems toprevent relative vertical displacement but permit relative rotationalmovement. When assembled, the coupling may be affixed by means of screwbolts 48 or the like. As shown, the coupling, when the valve head is inits highest operating position, will not come into contact with thevalve stem guide and consequently the coupling will not interfere withthe proper operation of the valve. In order to remove the valve head andthe upper stern, integral therewith, it is merely necessary to removethe coupling and then pull upwardly, on the head. In doing so it is notnecessary to remove the spring. When the valve head and stem arereplaced this also may be done without disturbing the spring. It is, ofcourse, understood that the releasable coupling may be formed of suchsize as to have its diameter equal to that of the two valve stemportions so that it may be free to slide in the valve stem guide. Thismay be accomplished in a similar manner to that discussed in connectionwith element I9 in Fig. 2. In this manner or by coupling the stemsdirectly together without the extra sleeve, the point of coupling may beabove the stem guide when the valve is pulled manually upwardly forremoval purposes.

Furthermore this arrangement tends toward the elimination of brokenvalve springs inasmuch as the valve head is free to rotate as it seatsand comes into contact with the seat before the extreme lower point ofmovement of the valve stem and thus the spring is notsubjected to theusual sudden stop when the valve engages its seat. Furthermore thecamshaft for operating the tappet may turn freely as there is no bindingin the valve head inasmuch as there is no positive twisting connectionbetween the spring and the valve head. or in other words because thevalve head is rotatable with respect to the spring.

As previously stated the wear on the valve stem by reason of the camaction on the lifting operation will be evenly distributed insofar asthe upper portion of the valve stem is concerned and consequently therewill be less tendency towards Valve stein guide leakage. Furthermore byreason of the slippage provided for in the valve stem, the valve willnot chatter as it seats.

We claim:

l. In a valve comprising a valve head, an articulated valve stem oneportion of which carries said valve head and is rotatable with respectto the other stem portion but reciprocable in unison therewith. 5

2. In combination in a valve having an articulated stem one portion ofwhich carries said valve head and which is reciprocable in unison butrelatively rotatable with respect to another portion of said valve stem,a seat for said valve, means 10 for actuating said rst stem portion forraising the Valve 01T its seat, and spring means connected to saidsecond stem portion for returning the valve to its seat.

3. In combination in a valve having an articul5 lated stem one portionof which carries said valve head and which is reciprocable in unison butrelatively rotatable with respect to another portion of said valve stem,a seat for said valve, means for actuating said second stern portion forrais- 2O ing the valve ofi its seat, and spring means connected to saidsecond stem portion for returning the valve to its seat and for rotatingsaid valve during its reciprocatory movements.

4. In combination in an internal combustion engine, a valve and a valveseat, said valve having an articulated valve stem one portion of whichcarries said valve and is rotatable with relation to but reciprocable inunison with another portion of said valve stem, a spring for returningthe valve to its seat, said spring being connected to said second valvestem portion and otherwise dissociated from the valve and said firstvalve stem portion.

5. In a valve comprising a valve head, an articulated valve stem oneportion of which carries said valve head and is rotatable with respectto the other stem portion but reciprocable in unison therewith and acoupling means for removably holding said portions together.

6. In combination in a valve having an articulated stem one portion ofwhich carries said valve head and which is reciprocable in unison butrelatively rotatable with respect to another portion of said Valve stem,a seat for said valve, means for actuating said first stem portion forraising the valve oi its seat, spring means connected to said secondstem portion for returning the valve to its seat, and a coupling meansfor removably holding said portions together. f 50 7. In combination ina valve having an articulated stem one portion of which carries saidValve head and which is reciprocable in unison but relatively rotatablewith respect to another portion of said valve stem, a seat for saidvalve, means for actuating said second stem portion for raising thevalve off its seat, spring means connected to said second stem portionfor returning the valve to its seat and for rotating said valve duringits reciprocatory movements, and a coupling means for removably holdingsaid portions together.

8. In combination in an internal combustion engine, a valve and a valveseat, said valve having an articulated valve stem one portion of whichcarries said valve and is rotatable with relation 55 to but reciprocablein unison with another portion of said valve stem, a spring forreturning the valve to its seat, said spring being connected to saidsecond valve stem portion and otherwise dissociated from the valve andsaid lfl'lrst valve-1o stem portion, and a coupling means for removablyholding said portions together.

JOHN JOSEPH DEWEY. GEORGE W. DOUGLAS.

